Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42574 (caspase-3)
 45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously reported that incubation of cultured astrocytes in Ca2 + -containing medium after exposure to Ca2 + -free medium caused Ca2 + influx followed by delayed cell death. Here, we studied the mechanisms underlying the Ca2 + -mediated injury of cultured astrocytes. Our results show that Ca2 + reperfusion injury of astrocytes appears to be mediated by apoptosis, as demonstrated by DNA fragmentation and prevention of death by caspase-3 inhibitors. Paradoxical Ca2 + challenge stimulated rapidly reactive oxygen species (ROS) production. Ca2 + reperfusion injury of astrocytes was influenced by several reagents which modified ROS production. When astrocytes were exposed to hydrogen peroxide (H2O2) for 30 min and then incubated without H2O2 for 1-5 days, cell toxicity including apoptosis was observed. Ca2 + reperfusion injury induced by Ca2 + depletion or H2O2 exposure was blocked by the iron chelator 1, 10-phenanthroline, the NF-kappaB inhibitor pyrrolidinedithiocarbamate and the calcineurin inhibitor FK506. Incubation in normal medium after H2O2 exposure rapidly increased the level of nuclear NF-kappaB p65 subunit, and the effect was blocked by 1,10-phenanthroline, pyrrolidinedithiocarbamate and FK506. These findings indicate that Ca2 + reperfusion-induced apoptosis is mediated at least partly by ROS production and ROS cause NF-kappaB activation in cultured astrocytes.
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PMID:Apoptosis in Ca2 + reperfusion injury of cultured astrocytes: roles of reactive oxygen species and NF-kappaB activation. 1059 46

Heat shock protein 70 (hsp70) is a stress-inducible protein that prevents apoptosis induced by a wide range of cytotoxic agents by an as yet undefined mechanism. The caspase family of cysteine proteases have been attributed a central role in the execution of apoptosis. However, several cases of caspase-independent apoptosis have been recently reported, suggesting that caspases may not be necessary for apoptosis in all cells. This study examines the protective role of hsp70 in both caspase-dependent and -independent apoptosis. Hydrogen peroxide (H2O2) used at low and high concentrations in Jurkat T cells induces caspase-dependent and -independent apoptosis, respectively. A hsp70-transfected Jurkat clone was used to observe the protection mediated by hsp70 during these two forms of apoptosis. Results reveal that hsp70 inhibits both caspase-dependent and -independent apoptosis. Furthermore, measurement of caspase-3 activity during caspase-dependent apoptosis revealed that caspase activation was inhibited in hsp70 transfectants. Early apoptotic events, such as mitochondrial depolarization, cytochrome c release, and increased intracellular calcium, were demonstrated to be common to both caspase-dependent and -independent H2O2-induced apoptosis. The inhibition of these events by hsp70 suggests that hsp70 may be an important anti-apoptotic regulator, functioning at a very early stage in the apoptotic pathway.
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PMID:Heat shock protein 70 inhibits caspase-dependent and -independent apoptosis in Jurkat T cells. 1085 54

To define the role of caspase-3 in H2O2-induced apoptosis, we introduced caspase-3 cDNA into MCF-7 breast carcinoma cells that otherwise lack caspase-3 expression. H2O2 treatment induced DNA fragmentation and nuclear condensation in the caspase-3-expressing cells, but not in the caspase-3-deficient cells. This indicated that caspase-3 is essential for nuclear events. However, H2O2 induced an externalization of membrane phosphatidylserine (PS) and cell death regardless of caspase-3 expression. These events were not suppressed by Ac-DEVD-CHO and Z-VAD-fmk, which inhibit DEVD-specific caspases and a broad spectrum of caspases, respectively. In Jurkat T cells, these inhibitors abolished H2O2-induced PS relocalization, but not cell death. Therefore, caspases appear to be dispensable for lethality by H2O2, but required for PS redistribution in a cell-type-specific manner.
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PMID:Caspase-dependent and -independent events in apoptosis induced by hydrogen peroxide. 1085 56

Glucocorticoids are known to promote apoptosis of eosinophils, normal and neoplastic lymphoid cells, and blastic cells in some patients with acute myeloid leukemia. We investigated the biochemical signal transduction pathways, in particular, the generation of reactive oxygen species (ROS) and activation of caspases in dexamethasone (DEX)-induced apoptosis of eosinophils, and we compared them with those in DEX-sensitive myeloid and lymphoid leukemia cell lines. The GC-receptor antagonist completely abolished DEX-induced apoptosis of eosinophils and leukemia cells. Among inhibitors related to the ROS system, diphenylene iodonium (DPI), a nicotinamide adenine dinucleotide diphosphate (NADPH) oxidase inhibitor, strongly inhibited both spontaneous and DEX-induced apoptosis of eosinophils at concentrations as low as 0.2 to 2 mumol/L, while promoting apoptosis of leukemia cells in a dose-dependent manner. Apocynin, another NADPH oxidase inhibitor, and antioxidants did not affect the apoptosis of eosinophils or leukemia cells. DEX treatment did not change intracellular production of O2- and H2O2, and it decreased the extracellular release of O2- in both cells. These results suggest little or no involvement of ROS generation in DEX-induced apoptosis of both cells. Although among peptide-based caspase inhibitors, only z-VAD-FMK, a broad caspase inhibitor, partially inhibited the apoptosis of eosinophils and leukemia cells, DEX treatment increased the activities of caspases 2-, 3-, 6-, and 8-like proteases assessed by colorimetry in both cells, suggesting the involvement of a similar caspase activation pathway in DEX-induced apoptosis in both cells. DPI markedly reduced caspase 3-like activity in eosinophils, while augmenting the activity in leukemia cells, indicating that DPI acts upstream of caspase 3 activation opposingly in both cells. Thus, the action of DPI in eosinophils seems peculiar in respect to apoptosis induction, and DPI appears to exert an influence on unknown targets rather than those involved in NADPH oxidase inhibition.
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PMID:Glucocorticoid-induced apoptotic pathways in eosinophils: comparison with glucocorticoid-sensitive leukemia cells. 1090 53

The ability of two different Jurkat sublines, termed standard and JM, to form DNA ladders was investigated after various apoptotic stimuli. Exposure to a broad spectrum of drugs interfering with signal transduction or cellular metabolism revealed distinct differences between both Jurkat sublines with regard to the pattern of DNA degradation. In standard Jurkat cells, internucleosomal DNA cleavage occurred only after treatment with the protein kinase inhibitor staurosporine. In contrast, the JM subline responded with internucleosomal DNA fragmentation to exposure to gemcitabine, cycloheximide or staurosporine. All drugs induced the formation of DNA fragments of about 50 kb in both sublines, as revealed by pulse field electrophoresis, except H2O2, which caused unspecific DNA degradation. The staurosporine-induced DNA ladder formation was accompanied by an increase in caspase-3 activity in both lines which, however, was considerably lower in Jurkat JM cells after gemcitabine or cycloheximide exposure. When the analysis of internucleosomal DNA degradation was carried out after mycoplasma infection, both Jurkat lines responded with DNA ladder formation after exposure to all drugs used (here only shown for the standard subline). Employing the zymogram technique, nuclease activities of 47 kDa and 54 kDa were detected in culture supernatants, cell homogenates and nuclear extracts only when mycoplasma-infected, whereas the samples obtained from mycoplasma-free sublines were nuclease-negative using this technique, indicating that these endonucleases were of mycoplasmal origin. After drug exposure, the mycoplasmal nucleases must have gained access to the cytoplasm and nuclei of their host cells by an unknown mechanism.
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PMID:Different sublines of Jurkat cells respond with varying susceptibility of internucleosomal DNA degradation to different mediators of apoptosis. 1095 23

As shown recently, the SV40 T/t-antigens (T/t-ag) exert a strong apoptotic activity in mouse mammary gland epithelial cells (ME-cells) leading to premature gland involution at late pregnancy. This high spontaneous cell death rate (20%) is also maintained in T/t-ag positive ME-tissue culture cell lines (e.g., 8/61-A), but not in those ME-cells that have switched off the SV40 T/t-transgene expression. In this study, we demonstrate for the first time that the T/t-ag sensitize ME-cells to oxidative stress leading to apoptosis. Treatment of the 8/61-A ME-cells with catalase, a scavenger of H2O2, completely blocked spontaneous cell death, which was linked to downregulation of caspase-3 activity. Furthermore, exposure of the cells to low concentrations of H2O2 highly increased the apoptosis rate. These findings suggest that the T/t-ag positive ME-cells contain either elevated levels of reactive oxygen species or reduced antioxidant activities. During spontaneous and H2O2-induced apoptosis, the activity of caspase-3 is significantly increased. In addition, the 8/61-A cells accumulated p21 and Bax proteins while the level of the anti-apoptotic protein Bcl-2 decreased implying a posttranscriptional regulation of apoptosis.
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PMID:SV40 T/t-antigens sensitize mammary gland epithelial cells to oxidative stress and apoptosis. 1102 93

The treatment of PC12 cells with H2O2 (100-500 microM) resulted in typical apoptotic changes including fragmentation and condensation of nuclei, and DNA fragmentation observed as DNA ladder. H2O2-induced apoptosis was associated with activation of caspase-3 as assessed by cleavage of specific fluorogenic substrate peptide and processing of procaspase-3 and poly(ADP-ribose) polymerase. However, formation of ceramide, which often locates upstream of caspase-3, was not observed. The inhibitory peptide relatively specific for caspase-3, z-DEVD-FMK and non-selective caspase inhibitor z-VAD-FMK inhibited activation of caspase-3 and apoptotic cell death. However, the relatively specific inhibitors, Ac-YVKD for caspase-1 and Ac-IETD for caspase-8/6, did not affect the occurrence of apoptotic cell death. As an upstream activation of caspase-3, induction of cytochrome c release followed by processing of procaspase-9 was observed by Western blotting, although the formation of intracellular ceramide was not observed. On the other hand, in PC12 cells overexpressing Bcl-2, the number of apoptotic cells was markedly decreased and activation of both caspases-9 and -3 was prevented. These results suggest that cytochrome c and caspase-9 initiate the activation of executor caspase-3 in H2O2-treated PC12 cells, and that Bcl-2 inhibits H2O2-induced release of cytochrome c from mitochondria and then proteolytic processing of procaspase-9.
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PMID:Activation of caspase-9 and -3 during H2O2-induced apoptosis of PC12 cells independent of ceramide formation. 1104 15

Reactive oxygen species (ROS) have been found to trigger apoptosis in tumor cells. At the same time, telomerase is found to be associated with malignancy and reduced apoptosis. However little is known about the linkage between ROS such as *OH and telomerase/telomere. To address the interrelations between *OH and telomerase/telomere in tumor cell killing, HeLa, 293 and MW451 cells were induced to undergo apoptosis with *OH radicals generated via Fe(2+)-mediated Fenton reactions (0.1 mM FeSO(4) plus 0.3-0.9 mM H2O2) and telomerase activity, telomere length were measured during apoptosis. We found that during *OH-induced apoptosis, telomere shortening took place while no changes in telomerase activity were observed. Our results suggest that *OH-induced telomere shortening is not through telomerase inhibition but possibly a direct effect of *OH on telomeres themselves indicating that telomere shortening but not telomerase inhibition is the primary event during *OH-induced apoptosis. Strikingly, we also found that *OH-induced apoptosis in HeLa cells is caspase-3-independent but is associated with reduction of mitochondrial transmembrane potential. Our results indicate that *OH triggers apoptotic tumor cell death through a telomere-related, caspase-independent pathway.
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PMID:Hydroxyl radical-induced apoptosis in human tumor cells is associated with telomere shortening but not telomerase inhibition and caspase activation. 1116 58

Previous studies have shown that under certain conditions some thiol-containing compounds can cause apoptosis in a number of different cell lines. Herein, we investigated the apoptotic pathways in HL-60 cells triggered by dithiothreitol (DTT), used as a model thiol compound, and tested the hypothesis that thiols cause apoptosis via production of hydrogen peroxide (H2O2) during thiol oxidation. The results show that, unlike H2O2, DTT does not induce apoptosis via a mitochondrial pathway. This is demonstrated by the absence of early cytochrome c release from mitochondria into the cytosol, the lack of mitochondrial membrane depolarization at early times, and the minor role of caspase 9 in DTT-induced apoptosis. The first caspase activity detectable in DTT-treated cells is caspase 3, which is increased significantly 1 - 2 h after the start of DTT treatment. This was shown by following the cleavage of both a natural substrate, DFF-45/ICAD, and a synthetic fluorescent substrate, z-DEVD-AFC. Cleavage of substrates of caspases 2 and 8, known as initiator caspases, does not start until 3 - 4 h after DTT exposure, well after caspase 3 has become active and at a time when apoptosis is in late stages, as shown by the occurrence of DNA fragmentation to oligonucleosomal-sized pieces. Although oxidizing DTT can produce H2O2, data presented here indicate that DTT-induced apoptosis is not mediated by production of H2O2 and occurs via a novel pathway that involves activation of caspase 3 at early stages, prior to activation of the common 'initiator' caspases 2, 8 and 9.
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PMID:Apoptosis induced by dithiothreitol in HL-60 cells shows early activation of caspase 3 and is independent of mitochondria. 1127 47

Exposure of neonatal rat cardiac myocytes to palmitate and glucose produces apoptosis as seen by cytochrome c release, caspase 3-like activation, DNA laddering, and poly(ADP-ribose) polymerase cleavage. The purpose of this study was to understand the role of reactive oxygen species in the initiation of programmed cell death by palmitate. We found that palmitate (but not oleate) produces inhibition of carnitine palmitoyltransferase I, accumulation of ceramide, and inhibition of electron transport complex III. These events are subsequent to cytochrome c release and loss of the mitochondrial membrane potential. No differences in H2O2 production or N-terminal c-Jun kinase phosphorylation were detected between myocytes incubated in palmitate and control myocytes (nonapoptotic) incubated in oleate. These results suggest that the palmitate-induced loss of the mitochondrial membrane potential is not associated with H2O2 synthesis and that a membrane potential is required to generate reactive oxygen species following ceramide inhibition of complex III.
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PMID:Fatty acid-induced apoptosis in neonatal cardiomyocytes: redox signaling. 1129


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